/*
 * This file contains helper functions for labeling support.
 *
 * Author : Richard Haines <richard_c_haines@btinternet.com>
 */

#include <stdlib.h>
#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include <errno.h>
#include "label_internal.h"

/*
 * The read_spec_entries and read_spec_entry functions may be used to
 * replace sscanf to read entries from spec files. The file and
 * property services now use these.
 */

/*
 * Read an entry from a spec file (e.g. file_contexts)
 * entry - Buffer to allocate for the entry.
 * ptr - current location of the line to be processed.
 * returns  - 0 on success and *entry is set to be a null
 *            terminated value. On Error it returns -1 and
 *            errno will be set.
 *
 */
static inline int read_spec_entry(char **entry, char **ptr, int *len,
                                  const char **errbuf)
{
    *entry = NULL;
    char *tmp_buf = NULL;

    while (isspace(**ptr) && **ptr != '\0') {
        (*ptr)++;
    }

    tmp_buf = *ptr;
    *len = 0;

    while (!isspace(**ptr) && **ptr != '\0') {
        if (!isascii(**ptr)) {
            errno = EINVAL;
            *errbuf = "Non-ASCII characters found";
            return -1;
        }
        (*ptr)++;
        (*len)++;
    }

    if (*len) {
        *entry = strndup(tmp_buf, *len);
        if (!*entry) {
            return -1;
        }
    }

    return 0;
}

/*
 * line_buf - Buffer containing the spec entries .
 * errbuf   - Double pointer used for passing back specific error messages.
 * num_args - The number of spec parameter entries to process.
 * ...      - A 'char **spec_entry' for each parameter.
 * returns  - The number of items processed. On error, it returns -1 with errno
 *            set and may set errbuf to a specific error message.
 *
 * This function calls read_spec_entry() to do the actual string processing.
 * As such, can return anything from that function as well.
 */
int read_spec_entries(char *line_buf, const char **errbuf, int num_args, ...)
{
    char **spec_entry, *buf_p;
    int len, rc, items, entry_len = 0;
    va_list ap;

    *errbuf = NULL;

    len = strlen(line_buf);
    if (line_buf[len - 1] == '\n') {
        line_buf[len - 1] = '\0';
    } else {
        /* Handle case if line not \n terminated by bumping
         * the len for the check below (as the line is NUL
         * terminated by getline(3)) */
        len++;
    }

    buf_p = line_buf;
    while (isspace(*buf_p)) {
        buf_p++;
    }

    /* Skip comment lines and empty lines. */
    if (*buf_p == '#' || *buf_p == '\0') {
        return 0;
    }

    /* Process the spec file entries */
    va_start(ap, num_args);

    items = 0;
    while (items < num_args) {
        spec_entry = va_arg(ap, char **);

        if (len - 1 == buf_p - line_buf) {
            va_end(ap);
            return items;
        }

        rc = read_spec_entry(spec_entry, &buf_p, &entry_len, errbuf);
        if (rc < 0) {
            va_end(ap);
            return rc;
        }
        if (entry_len) {
            items++;
        }
    }
    va_end(ap);
    return items;
}
